Cylinder arrangements consisting of a cylinder and a piston rod, especially in the case of a hydraulic cylinder arrangement having a hydraulic cylinder, are often employed for translatory force transmission. Such cylinder arrangements are sealed off vis-à-vis the surroundings by means of a usually multi-part sealing arrangement. In this context, part of the sealing arrangement consists of a wiper that seals off the sealing arrangement towards the surroundings. The task of the wiper is to strip off dirt, foreign particles and moisture from the piston rod as it enters the hydraulic cylinder. This prevents moisture or dirt from penetrating the sealing arrangement where it could cause premature wear and tear.
In this context, the wiper can be configured so as to be single-action or dual-action. A single-action wiper only has a wiper lip facing towards the surroundings. This lip keeps away impurities from the outside and prevents them from getting into the sealing arrangement. Dual-action wipers have a wiper lip facing towards the surroundings as well as a support lip facing in the direction of the space that is to be sealed off. On the one hand, the support lip brings about an improvement of the tilting stability of the wiper, which is mounted in a groove of the hydraulic cylinder. On the other hand, the support lip enhances the function of the sealing arrangement since the support lip strips off residues of hydraulic fluid that have passed through the sealing arrangement and keeps them inside the sealing arrangement. Such a dual-action wiper is disclosed, for example, in European patent specification EP 1 266 157 B1.
As already elaborated upon, the wiper is installed in a groove of the hydraulic cylinder, whereby the wiper lip and the support lip come into contact with the piston rod under radial pretension. However, when the piston rod is deflected radially under the effect of transverse forces, the installation space of the wiper changes, especially the gap between the cylinder and the piston rod. The gap becomes smaller on the deflected side of the piston rod and larger on the stressed side of the piston rod. The wipers known from the state of the art, however, are only capable of compensating for this deflection within the range of a few tenths of a millimeter. In the case of larger deflections, the wiper lip is no longer in contact with the entire circumference of the piston rod or else it is deformed to such a large extent that it can no longer strip off impurities over the entire circumference.
If, in order to solve this problem, the wipers are made of a softer material so that they can compensate for larger deflections of the piston rods, the lips of the wiper have to be configured relatively thick if they are very long so as to ensure contact of the wiper lip with the piston rod. When the available installation spaces are small, this causes severe deformations of the wiper lip, along with wide areas of contact with the piston rod. This results in high contact forces and undesired high friction.